A specific peptide with immunomodulatory activity from Pseudostellaria heterophylla and the action mechanism. (May 2020)

• Record Type: Journal Article
• Authors: Yang, Qian; Cai, Xixi; Huang, Muchen; Wang, Shaoyun
• Is Part Of: Journal of functional foods. Volume 68(2020)
• Publication Date: 2020-05
• Subjects: Arg-Gly-Pro-Pro-Pro -- Immunomodulatory peptide -- Pseudostellaria heterophylla -- RAW264.7 cells -- NF-κB -- Toll-like receptor 2; PPH Pseudostellaria heterophylla peptide -- RP-5 RGPPP -- T cells T lymphocytes -- B cells B lymphocytes -- NK natural killer -- TLRs toll like receptors -- ConA concanavalin A -- LPS lipopolysaccharide -- TNF-α tumor necrosis factor-α -- IL-10 interleukin-10 -- NO nitric oxide -- ROS reactive oxygen species -- MTT 3-(4, 5-Dimethyl-2-thiazolyl)-2, 5-diphenyl-2H-tetrazolium bromide -- ELISA enzyme-linked immunosorbent assay -- PDTC pyrrolidine dithiocarbamate -- HPLC high-performance liquid chromatography -- RP reversed-phase -- TFA trifluoroacetic acid -- LC-MS/MS liquid chromatography-tandem mass spectrometry -- CD circular dichroism -- DMSO dimethyl sulfoxide -- RT-qPCR reverse transcription quantitative polymerase chain reaction -- siRNA small interfering RNA -- SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis -- PVDF polyvinylidene fluoride -- TBST tris-buffered saline tween-20 -- ECL chemiluminescence -- SD standard deviation -- LSD least significant difference -- DMEM dulbecco's modified eagle medium -- PMSF phenylmethanesulfonyl fluoride -- GAPDH reduced glyceraldehyde-phosphate dehydrogenase -- NF-κB nuclear factor-κB -- IκB inhibitor of NF-κB; Functional foods -- Analysis -- Periodicals; Food -- Biotechnology -- Periodicals; Nutrition -- Periodicals; 613.2
• DOI: 10.1016/j.jff.2020.103887
• Languages: English
• ISSNs: 1756-4646

Abstract

Graphical abstract: Highlights: A novel immunomodulatory peptide was identified to be RGPPP in sequence. RGPPP was firstly found to activate macrophages. RGPPP significantly promoted TNF-α production, pinocytosis and TLR2 expression in macrophages. The action mechanism of RGPPP activating macrophages was firstly resolved through TLR2/NF-κB signaling pathway. Abstract: Pseudostellaria heterophylla protein hydrolysate has been reported to be a potential nutraceutical supplement to strengthen the immune system. A specific peptide from P. heterophylla protein hydrolysate with proliferation promotion effect on spleen lymphocytes was purified by RP-HPLC. The amino acid sequence of the peptide was determined to be RGPPP, with molecular weight of 522.29 Da. 100 μg/mL of RP-5 achieved the highest stimulation index of 1.27 on spleen lymphocytes and activated RAW264.7 cells resulting in up-regulating tumor necrosis factor-α (TNF-α) secretion to 827.24 pg/mL and elevating pinocytosis rate to 123.81%. Results of western-blot and siRNA experiments indicated that RP-5 activated nuclear factor-κB (NF-κB) signaling pathway through combining to TLR2 expressed on RAW264.7 cells surface. Furthermore, TNF-α secretion increased by RP-5 could be decreased to 401.68 pg/mL by pyrrolidine dithiocarbamate or BAY11-7082. These findings further the research progress of peptide with immunomodulatory activity and its action mechanism.